A MXene / vanadium dioxide / polymethyl methacrylate composite material and its preparation method and application

Abstract

The present invention discloses a MXene / vanadium dioxide / polymethyl methacrylate composite material and a preparation method and application thereof. Vanadium dioxide and polymethyl methacrylate are dissolved in an organic solvent, and ultrasonic stirring is performed to obtain a vanadium dioxide / polymethyl methacrylate mixed dispersion; the vanadium dioxide / polymethyl methacrylate mixed dispersion is added dropwise to a MXene film, and the mixture is evenly coated by scraping, and the mixture is placed in an oven for drying, and the organic solvent is volatilized to obtain a MXene / vanadium dioxide / polymethyl methacrylate composite material. Compared with existing thin film actuation materials, the composite material of the present invention has a very fast response speed, a multi-path response mode, and a stable actuation capability. At the same time, the composite material of the present invention has infrared stealth performance, and can also achieve the effect of remotely controlling movement in complex and changeable scenes. The multi-response actuator prepared by the present invention helps to expand the application of composite composite materials in intelligent fields such as actuators and micro robots.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a MXene / vanadium dioxide / polymethyl methacrylate composite material and a preparation method and application thereof. Background Art

[0002] In today's era of rapid technological development, the requirements for material performance in intelligent robots, military camouflage and many advanced technology fields are becoming increasingly stringent and diversified. In the field of intelligent robots, in order to achieve more complex and precise motion control and better environmental adaptability, materials need to have a variety of stimulus-responsive actuation properties. Traditional actuation materials can often only respond to a single stimulus, which limits the application of robots in complex environments. Moreover, robots may face the need to conceal themselves during the execution of tasks, so the stealth performance of materials is also crucial. Some existing robot materials either lack effective actuation performance or have poor stealth performance, making it difficult to simultaneously meet the multi-functional needs of intelligent robots.

[0003] In addition, in some other advanced technology fields, such as aerospace and special equipment manufacturing, higher requirements are also placed on the multifunctional integration of materials. Materials are required to have multiple properties under complex environmental conditions, such as good optical properties, mechanical properties, and response performance to different stimuli. However, the existing material systems are often difficult to meet these complex performance requirements at the same time, which limits the further development of related technical fields.

[0004] Chinese patent CN117987086A discloses a method for preparing a flexible vanadium dioxide film. The method uses one or more of polymer resins such as polyacrylonitrile, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinylidene fluoride hexafluoropropylene, ethylene oxide, polyethylene, polystyrene, etc. as a flexible substrate, physically blends nano-level vanadium dioxide, and synthesizes a flexible vanadium dioxide film. The patent solution only obtains a single-layer film.

[0005] Chinese patent CN117423999A discloses a multifunctional terahertz modulation composite material and its preparation method and application, including a substrate, a vanadium dioxide layer is provided on the substrate, a self-assembled MXene layer is formed on the vanadium dioxide layer, and the thickness of the MXene layer is 1 to 15 nm. By designing the thickness of the MXene layer of the composite material to be nanometer-level, not only the electron concentration of the MXene layer is increased, thereby increasing the modulation bandwidth of the composite material, but also the thinner MXene layer can absorb terahertz waves well, and is conducive to the transmission and reflection modulation of terahertz waves at high frequencies, and overall realizes the multifunctional regulation of reflection, transmission, and absorption of terahertz waves in a wide band of 0.5 to 4.5 THz. Although this scheme obtains a double-layer film, its preparation process requires the use of a magnetron sputtering process, which is complicated and expensive.

[0006] Chinese patent CN116560112A discloses a method for preparing an electrically driven active VO2 / MXene supersurface terahertz modulator, wherein a MXene film is prepared by vacuum filtration. A MXene supersurface is prepared by laser direct writing. A vanadium dioxide film is prepared by magnetron sputtering technology. The vanadium dioxide film on the quartz substrate prepared above is completely immersed in a buffered oxide etchant (BOE). The self-supporting vanadium dioxide film is salvaged from the water using the MXene supersurface prepared above, so that the vanadium dioxide film is suspended on the MXene supersurface, and then the VO2 / MXene composite supersurface is left to stand for 1 hour to wait for the two to be bonded and dried, thereby obtaining a VO2 / MXene composite supersurface. The MXene supersurface has the advantages of high flexibility and easy preparation. The VO2 / MXene terahertz modulator has the advantages of active control of terahertz waves, high modulation depth, and low trigger power. Although this scheme obtains a VO2 / MXene composite supersurface, it requires the use of magnetron sputtering technology to prepare a vanadium dioxide film, and the magnetron sputtering process is complex and costly.

[0007] In summary, developing a material that can simultaneously possess multi-stimulus responsive actuation and infrared stealth performance has important practical significance and application value, which is also the technical problem that the present invention is committed to solving. Summary of the invention

[0008] The purpose of the present invention is to provide a MXene / vanadium dioxide / polymethyl methacrylate composite material and a preparation method and application thereof.

[0009] The MXene / vanadium dioxide / polymethyl methacrylate composite material provided by the present invention has multiple stimulus response actuation capabilities and infrared stealth performance.

[0010] The purpose of the present invention can be achieved by the following technical solutions:

[0011] The present invention first provides a method for preparing a MXene / vanadium dioxide / polymethyl methacrylate composite material, which comprises the following steps:

[0012] (1) Preparation of a single-layer MXene film: Ti3AlC2MAX phase, lithium fluoride and hydrochloric acid are mixed and etched, washed to neutrality, and the supernatant is collected by ultrasonication and centrifugation to obtain a single-layer MXene dispersion, and a MXene film is obtained by vacuum filtration;

[0013] (2) preparing a vanadium dioxide / polymethyl methacrylate mixed dispersion: mixing vanadium pentoxide and dihydrated oxalic acid for hydrothermal reduction, washing and drying to obtain vanadium dioxide powder, dissolving vanadium dioxide and polymethyl methacrylate in an organic solvent, stirring and ultrasonicating to obtain a vanadium dioxide / polymethyl methacrylate mixed dispersion;

[0014] (3) Preparation of MXene / vanadium dioxide / polymethyl methacrylate composite material: Take a vanadium dioxide / polymethyl methacrylate mixed dispersion and add it dropwise onto the MXene film, apply it evenly by scraping, put it into an oven to dry, and evaporate the organic solvent to obtain a MXene / vanadium dioxide / polymethyl methacrylate composite material. The MXene / vanadium dioxide / polymethyl methacrylate composite material has a layered structure, including a MXene film and a vanadium dioxide / polymethyl methacrylate layer composed of vanadium dioxide particles and polymethyl methacrylate located on the MXene film.

[0015] In one embodiment of the present invention, in step (1), the molar ratio of Ti3AlC2MAX phase, lithium fluoride and hydrochloric acid is 1:12:3.6.

[0016] In one embodiment of the present invention, in step (1), the ultrasonic condition is 150-350 W power for 90-270 min.

[0017] In one embodiment of the present invention, in step (1), the centrifugal speed condition is 3000~5000 rpm.

[0018] In one embodiment of the present invention, in step (1), the thickness of the obtained MXene film is 20-40 μm.

[0019] In one embodiment of the present invention, in step (2), the molar ratio of vanadium pentoxide to oxalic acid dihydrate is 1:(1-3).

[0020] In one embodiment of the present invention, in step (2), the hydrothermal conditions are a temperature of 250-300° C. and a time of 24-48 hours.

[0021] In one embodiment of the present invention, in step (2), the mass ratio of vanadium dioxide to polymethyl methacrylate is 1:(1-4).

[0022] In one embodiment of the present invention, in step (2), the ratio of polymethyl methacrylate to organic solvent is 1 g: (3-5) ml.

[0023] In one embodiment of the present invention, in step (2), the organic solvent is selected from one or more of acetone or dimethylformamide.

[0024] In one embodiment of the present invention, in step (3), the amount of the vanadium dioxide / polymethyl methacrylate mixed dispersion added is 240-550 ml / m 2 .

[0025] In one embodiment of the present invention, in step (3), the scraping speed is 5-10 mm / s.

[0026] In one embodiment of the present invention, in step (3), the drying condition is drying at 60-80° C. for 5-10 min.

[0027] The present invention further provides a MXene / vanadium dioxide / polymethyl methacrylate composite material, which is prepared by the above method. The MXene / vanadium dioxide / polymethyl methacrylate composite material has a layered structure, including a MXene film and a vanadium dioxide / polymethyl methacrylate layer composed of vanadium dioxide particles and polymethyl methacrylate located on the MXene film.

[0028] Preferably, the MXene / vanadium dioxide / polymethyl methacrylate composite material is in the form of a film.

[0029] The present invention further provides an application of a MXene / vanadium dioxide / polymethyl methacrylate composite material, wherein the MXene / vanadium dioxide / polymethyl methacrylate composite material is used to prepare an actuating material.

[0030] The layered structure of MXene gives infrared light more internal reflection space, and the emitted infrared light is lost internally, which greatly reduces the infrared emissivity of the material surface and provides excellent infrared stealth capabilities. The hydrophilicity of its layers gives the composite material the ability to be actuated by humidity. When the humidity increases, the MXene layer absorbs water and causes a volume change. The difference in volume changes between the two layers causes the film morphology to change. In addition, the volume change of the phase change of vanadium dioxide can also bring thermal braking capabilities to the composite material. At the same time, the photothermal and electrothermal capabilities of MXene give the composite material more actuation response options. It is of great significance in the field of robot actuation.

[0031] Compared with the performance of thin film actuation materials synthesized by existing methods, the MXene / vanadium dioxide / polymethyl methacrylate composite material prepared by the present invention has a very fast response speed, a multi-path response mode, and a stable actuation ability. At the same time, the multi-response actuated MXene / vanadium dioxide / polymethyl methacrylate composite material prepared by the present invention has infrared stealth performance and can also achieve the effect of remote control movement in complex and changeable scenes. The multi-response actuator prepared by the present invention helps to expand the application of composite thin film materials in intelligent fields such as actuators and micro robots.

[0032] Specifically, compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The stacked structure and metal-like properties of MXene in the present invention cause infrared rays to be reflected back and forth between the layers and consumed, showing a low infrared emissivity and excellent infrared stealth performance. At the same time, the photothermal properties and excellent conductivity can provide energy for vanadium dioxide to undergo phase change (that is, MXene can transfer heat to vanadium dioxide, causing vanadium dioxide to undergo phase change).

[0034] 2. The unit cell structure of vanadium dioxide in the present invention changes during phase transition, and the large volume change before and after the phase transition gives the composite material the ability to respond to heat, light, and electricity. At the same time, the stacking structure of the hydrophilic sheets of MXene provides the ability to be actuated by humidity.

[0035] 3. The polymethyl methacrylate in the present invention wraps the vanadium dioxide to make it a whole, prevents its oxidation, transfers the cumulative deformation, and makes the vanadium dioxide and MXene fit well.

[0036] 4. The multi-response actuation and infrared stealth capabilities of the MXene / vanadium dioxide / polymethyl methacrylate composite material prepared by the present invention are of great significance to intelligent robots and military defense fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 This is the infrared stealth performance of the MXene / vanadium dioxide / polymethyl methacrylate composite material in Example 3.

[0039] Figure 2The multi-responsive actuation performance of the MXene / vanadium dioxide / polymethyl methacrylate composite material in Example 3: (a) thermal response actuation; (b) light response actuation; (c) electrical response actuation; and (d) humidity response actuation. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0041] Example 1

[0042] This embodiment is a method for preparing a MXene / vanadium dioxide / polymethyl methacrylate composite material with multi-response actuation and infrared stealth capabilities, which is carried out according to the following steps.

[0043] (1) Preparation of single-layer MXene film: 10 mL of deionized water and 30 mL of hydrochloric acid were mixed in a Teflon-lined reactor, 2.0 g of Ti3AlC2MAX phase and 3.2 g of lithium fluoride were added, and then the mixture was stirred in an oil bath at 37°C and etched for 24 h. After etching, the mixture was washed with deionized water until pH = 7, and then the aqueous solution was placed in an ultrasonic machine with a power of 150 W for 270 min to separate the multilayer MXene into a single layer. The upper layer liquid was separated by centrifugation at 3000 rpm, and the concentration of the single-layer MXene solution was determined by vacuum filtration and weighing (since the concentration of the MXene solution prepared each time is unknown, the concentration needs to be measured. For example, 1 ml of the solution is filtered to form a film. If the mass of the obtained film is 5 mg, then the solubility of the solution is 5 mg / ml. At this time, if a 20 mg film is required, 4 ml of the solution is required). Finally, a solution with a MXene content of 20 mg is measured and vacuum filtered to obtain a MXene film;

[0044] (2) Preparation of vanadium dioxide / polymethyl methacrylate mixed dispersion: 1.82 g of vanadium pentoxide and 2.52 g of oxalic acid dihydrate were dissolved in 60 mL of deionized water, poured into a hydrothermal reactor and placed in a digital display electric heating blast drying oven for reaction at 250 °C for 48 h, washed with deionized water and anhydrous ethanol respectively, and dried in a vacuum drying oven at 60 °C for 12 h to obtain VO2 particles. 1 g of vanadium dioxide and 1 g of polymethyl methacrylate were dissolved in 3 ml of acetone, stirred and ultrasonicated to obtain a vanadium dioxide / polymethyl methacrylate mixed dispersion;

[0045] (3) Preparation of MXene / vanadium dioxide / polymethyl methacrylate composite material: 0.3 ml of the vanadium dioxide / polymethyl methacrylate mixed dispersion was added dropwise onto the MXene film obtained in the above step (1), and the film was evenly coated at a speed of 5 mm / s. The film was placed in an oven and dried at 60°C for 10 min to evaporate the organic solvent, thereby obtaining a MXene / vanadium dioxide / polymethyl methacrylate composite material.

[0046] The MXene / vanadium dioxide / polymethyl methacrylate composite material prepared in this embodiment has multi-response actuation capability, thermal response actuation can achieve 80° change within 3s, light response actuation can achieve 100° change within 15s, electrical response actuation can achieve fast response within 2s, and humidity response can achieve 60° change within 30s. In addition, the composite material also has certain infrared stealth performance.

[0047] Example 2

[0048] This embodiment provides a method for preparing a MXene / vanadium dioxide / polymethyl methacrylate composite material with multi-response actuation and infrared stealth capabilities, which is carried out according to the following steps.

[0049] (1) Preparation of single-layer MXene film: 10 mL of deionized water and 30 mL of hydrochloric acid were mixed in a Teflon-lined reactor, 2.0 g of Ti3AlC2MAX phase and 3.2 g of lithium fluoride were added, and then stirred in an oil bath at 37°C and etched for 24 h. After etching, the mixture was washed with deionized water until pH = 7, and then the aqueous solution was placed in an ultrasonic machine at a power of 350 W for 90 min to separate the multilayer MXene into a single layer. The upper layer of liquid was separated by centrifugation at a speed of 5000 rpm, and the concentration of the single-layer MXene solution was determined by vacuum filtration and weighing. Finally, a solution with a MXene content of 40 mg was measured and vacuum filtered to obtain a MXene film;

[0050] (2) Preparation of vanadium dioxide / polymethyl methacrylate mixed dispersion: 1.82 g of vanadium pentoxide and 2.52 g of oxalic acid dihydrate were dissolved in 60 mL of deionized water, poured into a hydrothermal reactor and placed in a digital display electric heating blast drying oven for reaction at 250 °C for 48 h, washed with deionized water and anhydrous ethanol respectively, and dried in a vacuum drying oven at 60 °C for 12 h to obtain VO2 particles. 1 g of vanadium dioxide and 4 g of polymethyl methacrylate were dissolved in 20 ml of dimethylformamide, stirred and ultrasonicated to obtain a vanadium dioxide / polymethyl methacrylate mixed dispersion;

[0051] (3) Preparation of MXene / vanadium dioxide / polymethyl methacrylate composite material: Take 0.7 ml of the vanadium dioxide / polymethyl methacrylate mixed dispersion and add it dropwise onto the MXene film obtained in step (1), apply it evenly at a speed of 10 mm / s, put it in an oven and dry it at 70°C for 5 min to evaporate the organic solvent, thereby obtaining a MXene / vanadium dioxide / polymethyl methacrylate composite material.

[0052] The MXene / vanadium dioxide / polymethyl methacrylate composite material prepared in this embodiment has multi-response actuation capability, thermal response actuation can achieve a change of 75° within 4s, light response actuation can achieve a change of 92° within 17s, electrical response actuation can achieve a fast response within 3s, and humidity response can achieve a change of 55° within 27s. In addition, the composite material also has certain infrared stealth performance.

[0053] Example 3

[0054] This embodiment is a method for preparing a MXene / vanadium dioxide / polymethyl methacrylate composite material with multi-response actuation and infrared stealth capabilities, which is carried out according to the following steps.

[0055] (1) Preparation of single-layer MXene film: 10 mL of deionized water and 30 mL of hydrochloric acid were mixed in a Teflon-lined reactor, 2.0 g of Ti3AlC2MAX phase and 3.2 g of lithium fluoride were added, and then stirred in an oil bath at 37°C and etched for 24 h. After etching, the mixture was washed with deionized water until pH = 7, and then the aqueous solution was placed in an ultrasonic machine and ultrasonicated at a power of 300 W for 120 min to separate the multilayer MXene into a single layer. The upper layer of liquid was separated by centrifugation at 3500 rpm, and the concentration of the single-layer MXene solution was determined by vacuum filtration and weighing. Finally, a solution with a MXene content of 30 mg was measured and vacuum filtered to obtain a MXene film;

[0056] (2) Preparation of vanadium dioxide / polymethyl methacrylate mixed dispersion: 1.82 g of vanadium pentoxide and 2.52 g of oxalic acid dihydrate were dissolved in 60 mL of deionized water, poured into a hydrothermal reactor and placed in a digital display electric heating blast drying oven for reaction at 250 °C for 48 h, washed with deionized water and anhydrous ethanol respectively, and dried in a vacuum drying oven at 60 °C for 12 h to obtain VO2 particles. 1 g of vanadium dioxide and 3 g of polymethyl methacrylate were dissolved in 5 ml of acetone and 5 ml of dimethylformamide, and stirred with ultrasound to obtain a vanadium dioxide / polymethyl methacrylate mixed dispersion;

[0057] (3) Preparation of MXene / vanadium dioxide / polymethyl methacrylate composite material: 0.5 ml of the vanadium dioxide / polymethyl methacrylate mixed dispersion was added dropwise onto the MXene film obtained in step (1), and the mixture was evenly coated at a speed of 7 mm / s. The mixture was placed in an oven and dried at 65°C for 7 min to evaporate the organic solvent, thereby obtaining a MXene / vanadium dioxide / polymethyl methacrylate composite material.

[0058] The MXene / vanadium dioxide / polymethyl methacrylate composite material prepared according to Example 3 was tested for its multi-response actuation performance.

[0059] The MXene / vanadium dioxide / polymethyl methacrylate composite material prepared in Example 3 was placed on a constant temperature hot plate at 80°C. It was observed that the composite material deformed rapidly within 2 seconds, and the bending angle reached about 90°. Figure 2 (a) is consistent with theoretical expectations.

[0060] Under the irradiation of sunlight, the temperature of the MXene / vanadium dioxide / polymethyl methacrylate composite material prepared in Example 3 gradually rises, the vanadium dioxide in the vanadium dioxide / polymethyl methacrylate layer undergoes a phase transition, and the composite material begins to gradually unfold, with an angle change of nearly 125°. Figure 2 (b) shows the expected photoactuated performance.

[0061] Using an adjustable DC regulated current to apply a 3V voltage to both ends of the composite material, the composite material opens rapidly and can maintain the open state continuously. When the voltage drops back to 0V, the composite material curls up. Figure 2 As shown in (c), the angle regulation is as expected and the response speed is faster than photoactuation.

[0062] Use a small humidifier to spray humidify the composite material, and the composite material will gradually flatten, and the angle change is about 70°, such as Figure 2 (d) shows the humidity-actuated performance.

[0063] In addition, the composite material was covered on the index finger joint and infrared images were taken with a handheld infrared camera. The covered joint was integrated with the background, e.g. Figure 1 As shown, it proves that it has excellent infrared stealth performance.

[0064] Example 4

[0065] This embodiment provides a method for preparing a MXene / vanadium dioxide / polymethyl methacrylate composite material with multi-response actuation and infrared stealth capabilities. This embodiment is different from Example 3 in that the organic solvent used in step (2) is 12 ml of acetone.

[0066] The MXene / vanadium dioxide / polymethyl methacrylate composite material prepared in this embodiment has multi-response actuation capability, thermal response actuation can achieve a change of 65° within 4s, light response actuation can achieve a change of 88° within 18s, electrical response actuation can achieve a fast response within 4s, and humidity response can achieve a change of 56° within 34s. In addition, the composite material also has certain infrared stealth performance.

[0067] Example 5

[0068] This embodiment is a method for preparing a MXene / vanadium dioxide / polymethyl methacrylate composite material with multi-response actuation and infrared stealth capabilities. The difference between this embodiment and Example 3 is that the organic solvent used in step (2) is 12 ml of dimethylformamide.

[0069] The MXene / vanadium dioxide / polymethyl methacrylate composite material prepared in this embodiment has multi-response actuation capability, thermal response actuation can achieve a change of 77° within 3s, light response actuation can achieve a change of 80° within 17s, electrical response actuation can achieve a fast response within 3s, and humidity response can achieve a change of 63° within 27s. In addition, the composite material also has certain infrared stealth performance.

[0070] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0071] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a MXene / vanadium dioxide / polymethyl methacrylate composite material, characterized in that: The method comprises the following steps: (1) Preparation of a single-layer MXene film: Ti3AlC2MAX phase, lithium fluoride and hydrochloric acid are mixed and etched, washed to neutrality, and the supernatant is collected by ultrasonication and centrifugation to obtain a single-layer MXene dispersion, and a MXene film is obtained by vacuum filtration; (2) preparing a vanadium dioxide / polymethyl methacrylate mixed dispersion: mixing vanadium pentoxide and dihydrated oxalic acid for hydrothermal reduction, washing and drying to obtain vanadium dioxide powder, dissolving vanadium dioxide and polymethyl methacrylate in an organic solvent, stirring and ultrasonicating to obtain a vanadium dioxide / polymethyl methacrylate mixed dispersion; (3) Preparation of MXene / vanadium dioxide / polymethyl methacrylate composite material: Take a vanadium dioxide / polymethyl methacrylate mixed dispersion and add it dropwise onto the MXene film, apply it evenly by scraping, put it into an oven to dry, and evaporate the organic solvent to obtain a MXene / vanadium dioxide / polymethyl methacrylate composite material. The MXene / vanadium dioxide / polymethyl methacrylate composite material has a layered structure, including a MXene film and a vanadium dioxide / polymethyl methacrylate layer composed of vanadium dioxide particles and polymethyl methacrylate located on the MXene film.

2. The method for preparing the MXene / vanadium dioxide / polymethyl methacrylate composite material according to claim 1, characterized in that: In step (1), the molar ratio of Ti3AlC2MAX phase, lithium fluoride and hydrochloric acid is 1:12:3.

6.

3. The method for preparing the MXene / vanadium dioxide / polymethyl methacrylate composite material according to claim 1, characterized in that: In step (1), the ultrasonic condition is 150-350 W for 90-270 min; the centrifugal speed condition is 3000-5000 rpm.

4. The method for preparing the MXene / vanadium dioxide / polymethyl methacrylate composite material according to claim 1, characterized in that: In step (1), the thickness of the obtained MXene film is 20~40 μm.

5. The method for preparing the MXene / vanadium dioxide / polymethyl methacrylate composite material according to claim 1, characterized in that: In step (2), the mass ratio of vanadium dioxide to polymethyl methacrylate is 1:(1-4); In step (2), the ratio of polymethyl methacrylate to organic solvent is 1 g: (3-5) ml.

6. The method for preparing the MXene / vanadium dioxide / polymethyl methacrylate composite material according to claim 1, characterized in that: In step (2), the organic solvent is selected from one or more of acetone and dimethylformamide.

7. The method for preparing the MXene / vanadium dioxide / polymethyl methacrylate composite material according to claim 1, characterized in that: In step (3), the amount of the vanadium dioxide / polymethyl methacrylate mixed dispersion added is 240-550 ml / m 2 .

8. The method for preparing the MXene / vanadium dioxide / polymethyl methacrylate composite material according to claim 1, characterized in that: In step (3), the scraping speed is 5-10 mm / s; In step (3), the drying condition is drying at 60-80°C for 5-10 min.

9. A MXene / vanadium dioxide / polymethyl methacrylate composite material, characterized in that: The MXene / vanadium dioxide / polymethyl methacrylate composite material is prepared by the preparation method according to any one of claims 1 to 8, and is in the form of a film. The MXene / vanadium dioxide / polymethyl methacrylate composite material is a layered structure, including a MXene film and a vanadium dioxide / polymethyl methacrylate layer composed of vanadium dioxide particles and polymethyl methacrylate located on the MXene film.

10. An application of the MXene / vanadium dioxide / polymethyl methacrylate composite material as claimed in claim 9, characterized in that: The MXene / vanadium dioxide / polymethyl methacrylate composite material is used to prepare an actuating material.

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